We've already pointed you to the best websites for men, best websites for women, and best websites for a dose of laughter. And while those are all great and useful, there are still millions of other sites on the web, many of which you've probably never heard of before.

Keep reading to discover lesser-known sites that may blow your mind or even change your life. You won't find all of them useful, but I guarantee that at least one of them will seriously impress you.

We've divided them into four categories: Creative, Educational, Arts and Entertainment, and Utilities. Feel free to jump ahead to any of them.

Creative

1. Turn YouTube Videos Into Guitar Chords

Chordify can take any song on YouTube, SoundCloud, or Deezer and figure out the chords for you. You can also upload MP3, M4A, or OGG files and get chords for them, too. It's free, but Premium users get extra features like chord sheets, transpositions, playback, etc.

2. Easy Color Schemes

Coolors is a color scheme generator that creates random palettes that always work. You can tweak generated palettes to your liking and save them for later. Or you can upload an image and have Coolors generate a palette based on the colors in the image.

3. Free Sound Effects

FreeSound is a massive collection of royalty-free sound files. A lot of them are licensed as CC0, but many of them fall under other licenses too, so be sure to check restrictions for each sound you download. This is a great resource if you make videos, develop games, or just need to spice up a presentation.

4. Free Game Assets

OpenGameArt is a massive collection of free game-related assets, including 2D and 3D art. Restrictions vary from asset to asset, but they're all free and many are licensed under CC0. It's a great way to find inspiration for your own pixel art.

Educational

5. Free World-Class College Courses

You can find all kinds of online courses these days on sites like Coursera, edX, Khan Academy, and Udemy... but you should start with Academic Earth. You'll find thousands of excellent courses, and the site's core belief is that "everyone has the right to a world-class education."

6. The Most Helpful Math Tutorials

Despite what you may think, everyone can be good at math -- all you need is someone who knows how to teach it properly. PatrickJMT offers the absolute best math lessons of any site on the web. He covers everything from basic Algebra and Trigonometry to advanced Calculus, Discrete Math, and Differential Equations, all available as free online videos.

7. Learn Any Skill for Free on the Web

NoExcuseList is a compilation of free online resources for learning new skills. If you ever wanted to learn something but didn't know where to start, now you have no excuse. Lists are organized into categories, including Academics, Cooking, DIY, and Other.

8. Open Access to Any Scientific Paper

Most scientific papers are locked behind paywalls and subscriptions, limiting public access to important research. Sci-Hub believes that this slows down the development of science, and aims to provide access to any scientific paper for anybody who wants it. Unlock any paper by entering its URL, PMID, or DOI -- or simply search through Sci-Hub's huge database.

9. Independent Research on Supplements

Supplements are tricky because they aren't well-regulated and there's a lot of misinformation on the web. Everyone has an agenda. In response, Examine launched in 2011. They read through the actual research, present unbiased facts to readers, and update their stances whenever new research comes to light. You'll be surprised by what they've found over the years.

10. Exercise Lists for Every Muscle Group

Have you ever wanted to strengthen a certain muscle but didn't know which exercises to do? Head over to the MuscleWiki. This awesome site lets you click on any muscle and see a list of all exercises that involve that particular muscle. It's a must-use resource for fitness newbies.

11. The Right Way to Lace Your Shoes

Hear me out -- it's not as silly as it sounds. If certain parts of your feet ache, or if you have recurring blisters or calluses, then you might benefit by changing the way you lace your shoes. Ian's Shoelace Site has everything you'd ever need to know about shoelaces, and you won't regret checking it out.

12. Predictions on the Future of Humankind

What will be true by 2030? 2040? 2050? How about 2100? Or even 10,000 AD and beyond? Future Timeline offers predictions about the future based on facts and ongoing scientific research. Every bit of speculation (e.g. "Bangkok abandoned due to flooding in 2031") is backed up by at least one source.

Arts and Entertainment

13. Listen to Police Radios in Metro Cities

You Are Listening To offers 24/7 live streams of police radio channels from approximately 30 cities (the only non-U.S. cities are Brisbane, Montreal, and St. Petersburg). Each stream is set to unsettling ambient music, turning this otherwise mundane experience into an incredible one.

14. Listen to Radio Stations Around the World

Radio Garden lets you tune into nearly any radio station in the world. It provides you with an interactive map with green dots, each dot representing a live radio station. It's a fun way to kill some time, and one of the best ways to find interesting internet radio stations.

15. Listen to Shortwave Radio Waves

Here's one more radio-related site worth mentioning. Wide-band WebSDR lets you control a shortwave receiver located at the University of Twente, providing dozens of tweakable settings to allow you to explore shortwave space at your leisure. It's a fun and free way to play around with amateur radio.

16. Every Music Genre to Ever Exist

Every Noise at Once is a mapping of every music genre to ever exist, with each genre placed in relative proximity to other similar genres. This makes it a great way to discover new flavors of music that you'll love. Don't forget that you can also discover new music with Spotify as well as these other music websites.

In 2014, the New York Metropolitan Museum of Art released over 400,000 works of art as free high-resolution images available on the web. Want to expand your artistic tastes and knowledge? Check out the collection right now, which you can filter by artist, material, geographic location, era, department, and more.

18. Play Hundreds of Retro Games Online

Play Retro Games is an online emulator that lets you play all kinds of older games right in your browser for free. Supported systems include NES, SNES, Sega Genesis, GBA, and more. If you run out of games to enjoy, check out these other sites for playing retro games.

19. Google Maps Street View Guessing Game

GeoGuessr is a fun way to kill some time. It'll present you with a Street View location from somewhere in the world, and you have to pinpoint where it is on a map. The closer you are, the more points you earn. Not only is it fun, but you'll probably learn a lot along the way. Try it the next time you're bored online.

Utilities

20. Real-Time Map of Global Emergencies

This incredible map by RSOE EDIS shows real-time occurrences of emergencies, hazards, alerts, and other notable events (e.g. earthquakes, storms, explosions, diseases, vehicle accidents, etc.). You can zoom in regions around the world, so it's not just limited to the United States.

21. Compare Cost of Living Between Cities

If you're thinking of moving to another city, you should absolutely use the Cost of Living Comparison by NUMBEO. Just type in both cities and it'll tell you the differences in grocery prices, rent prices, restaurant prices, etc. Moving to an area with a higher cost of living on the same salary is basically making yourself poorer, so avoid that mistake with this site!

22. Check If Your Online Accounts Were Ever Hacked

HaveIBeenPwned is a simple tool that checks if your usernames or email addresses have ever been breached and released by hackers. Any time you're "pwned," you should change the passwords on compromised accounts. Do this at least once a year as part of an annual security and privacy checkup.

23. Generate Fake Identities for Online Accounts

If you want to sign up for an online account or sign an online petition without giving away your personal details, use the Fake Name Generator to create a false name, address, phone number, birthday, financial details, and more. This is one way to stop sharing private details online. (But don't give fake details for legally-binding accounts, which could constitute fraud!)

24. Background Noise for True Relaxation

While background noise apps are now commonplace, only one can be the best of the best, and that one is MyNoise. Created by a sound engineer who knows the science behind effective noise machines, MyNoise offers hundreds of different sounds to soothe and relax, from tonal drones to natural noises, from soundscapes to industrial ambience. It's amazing. Try it.

25. Create Professional Resumes

Are you in between jobs right now? If you have a LinkedIn account, you can turn it into a resume in the blink of an eye. But if you don't use LinkedIn, then you should consider using Creddle. This tool helps you create professional-looking resumes that are designed to help you land more interviews.

If the job search itself is bringing you down, check out these tips for a more productive job search as well as these must-have Chrome extensions for finding and landing a job.

How many of these nifty sites did you already know about? Are there any other cool sites that deserve a mention? Share with us in a comment below!

Image Credits: A and N photography/Shutterstock